GM DEXRON II

GM DEXRON II is the original General Motors approval for automatic transmissions, which sets requirements for viscosity, thermal stability and oxidation protection. The specification calls for the use of transmission oil with a base viscosity of 75 W‑90 (or equivalent SAE 75) and the ability to maintain a stable molecular size at temperatures up to 120 °C, ensuring smooth shifting and minimizing gear wear. DEXRON II is intended for older GM automatic transmissions, in particular 4‑speed and 5‑speed gearboxes of Chevrolet, GMC, Cadillac and Buick models produced up to the early 1990s. Although this approval does not specify special requirements for DPF or catalyst systems, it is compatible with conventional transmissions without post‑turbo cleaning devices. In modern GM models DEXRON II is often replaced by newer approvals DEXRON III F/G/H or DEXRON VI, which remain backward compatible, so the use of oil approved to DEXRON II is also suitable for these updated standards.